Flexible swirlers

ABSTRACT

A swirler includes a swirler body and a plurality of axial swirl vanes extending radially outward from the swirler body. At least one of the swirler body or vanes includes a spring channel defined therethrough. A fuel injector for a gas turbine engine can include an inner air swirler and/or outer air swirler as described above.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to swirlers, and more particularly to airswirlers such as used in pure airblast fuel injectors for gas turbineengines.

2. Description of Related Art

A variety of devices and methods are known in the art for injecting fuelinto gas turbine engines. Of such devices, many are directed toinjecting fuel into combustors of gas turbine engines under hightemperature conditions.

In a fuel injector for a gas turbine engine, inner air swirlers are usedto impart a tangential velocity component to the air, setting up aradial pressure gradient that biases the highest velocity air towardsthe outer diameter of the air passage where the air meets up with thefuel. This higher velocity improves atomization of the fuel. In additionto the inner air swirlers, outer air swirlers are also present which,along with the inner air circuit, help to distribute the fuel into thecombustor.

Air swirlers are subjected to hot air from the compressor, which can beat temperatures as high as 1300° F. (704° C.), and these temperatureswill rise as the demand for higher compression ratios continues. Yetthere are other areas of the injector in direct contact with fuel, whichtends to remains much cooler than the compressor discharge air. As aconsequence, the vanes in injector air swirlers act like heat exchangingfins. Due to their relatively small mass and heat fin behavior, theseair swirlers tend to heat up faster than their surrounding structure.This is especially the case for transient events. Another drivingmechanism for thermal stress in the outer air swirler is radiation fromthe flame front within the combustor. As design requirements drivetoward ever hotter compressor discharge temperatures, compressordischarge air is becoming less effective at cooling outer air swirlersurfaces that heat up due to flame radiation.

As current and future engines continue to increase in operating pressureratio, the temperatures exiting from the compressor are expected toclimb, while fuel temperatures are expected to remain below carbonformation temperatures. Therefore, the temperature differential to whichfuture fuel injectors are expected to be subjected is expected to grow,leading to higher stresses and presenting limitations on the life of theinjector.

Such conventional methods and systems have generally been consideredsatisfactory for their intended purpose. However, there is still a needin the art for improved swirlers and injectors. The present disclosureprovides a solution for this need.

SUMMARY OF THE INVENTION

A swirler includes a swirler body and a plurality of axial swirl vanesextending radially outward from the swirler body. At least one of theswirler body or vanes includes a spring channel defined therethrough.

The swirler body can include an inner air swirler bullet with an openingdefined in a downstream end thereof, wherein a plurality of springchannels are defined through the bullet, each extending from a pointupstream of the opening and extending to the opening of the bullet. Thespring channels defined through the bullet can extend helically aboutthe bullet.

Each of the vanes can include a spring channel defined therethrough,extending from an upstream portion of the vane to a channel opening at atrailing edge of the vane. It is also contemplated that each of thevanes can include a spring channel defined therethrough, extending froma downstream portion of the vane to a channel opening at a leading edgeof the vane. For example, each of the vanes can include a sigmoid springhaving a first spring channel defined therethrough, extending from anupstream portion of the vane to a channel opening at a trailing edge ofthe vane, and a second spring channel defined therethrough radiallyspaced apart from the first spring channel, extending from a downstreamportion of the vane to a channel opening at a leading edge of the vane.

The spring channels described herein can each have a labyrinthinecross-sectional profile to inhibit flow leakage through the springchannels. The spring channels described herein can include a stressreduction feature, e.g., one end of the spring channel can terminate ata stress reducer bore.

In accordance with certain embodiments, the swirler body includes abarrel of an outer air swirler, wherein a plurality of spring channelsare defined through the barrel. The spring channels defined through thebarrel can extend helically about the barrel.

A fuel injector for a gas turbine engine includes an injector bodyhaving a feed arm with a nozzle body connected thereto. A fuel conduitfluidly connects a fuel inlet portion of the feed arm to a fuel circuitin the nozzle body to form a fuel path through the injector body. Anouter air swirler is operatively connected to the nozzle body outboardof the fuel circuit. The outer air swirler includes a barrel with aplurality of swirl vanes extending radially outward from the barrel. Aninner air swirler is operatively connected to the nozzle body inboard ofthe fuel circuit. The inner air swirler includes an inner air swirlerbullet with a plurality of swirl vanes extending radially outward fromthe bullet. At least one of the barrel, the bullet, the swirl vanes ofthe outer air swirler, or the swirl vanes of the inner air swirlerincludes a spring channel defined therethrough.

These and other features of the systems and methods of the subjectdisclosure will become more readily apparent to those skilled in the artfrom the following detailed description of the preferred embodimentstaken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those skilled in the art to which the subject disclosureappertains will readily understand how to make and use the devices andmethods of the subject disclosure without undue experimentation,preferred embodiments thereof will be described in detail herein belowwith reference to certain figures, wherein:

FIG. 1 is a partial cross-sectional side elevation view of an exemplaryembodiment of a fuel injector constructed in accordance with the presentdisclosure, showing the feed arm and nozzle body;

FIG. 2 is a cross-sectional side elevation view of the nozzle body ofFIG. 1, showing the inner and outer air swirlers;

FIG. 3 is a perspective view of the inner air swirler of FIG. 2, showingthe spring channels in the vanes;

FIG. 4 is a perspective view of another exemplary embodiment of an innerair swirler, showing each vane including a sigmoid spring with twoopposed spring channels;

FIG. 5 is a perspective view of another exemplary embodiment of an innerair swirler, showing the bullet with spring channels defined therein;

FIG. 6 is a perspective view of a portion of the outer air swirler ofFIG. 2, showing the spring channels in the vanes;

FIG. 7 is a perspective view of a portion of another exemplaryembodiment of an outer air swirler, showing each vane including asigmoid spring with two opposed spring channels;

FIG. 8 is a partially cut away perspective view of a portion of anotherexemplary embodiment of an outer air swirler, showing the barrel withspring channels defined therein;

FIG. 9 is a perspective view of the outer air swirler of FIG. 8, showingthe spring channels;

FIG. 10 is a side elevation view of a portion of another exemplaryembodiment of an inner air swirler, showing a vane with a labyrinthinecross-sectional profile to reduce flow leakage through the vane; and

FIG. 11 is an end elevation view of the inner air swirler of FIG. 10,showing the labyrinthine cross-sectional profile of the spring channelsin the vanes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made to the drawings wherein like referencenumerals identify similar structural features or aspects of the subjectdisclosure. For purposes of explanation and illustration, and notlimitation, a partial view of an exemplary embodiment of a fuel injectorconstructed in accordance with the disclosure is shown in FIG. 1 and isdesignated generally by reference character 100. Other embodiments offuel injectors in accordance with this disclosure, or aspects thereof,are provided in FIGS. 2-11, as will be described. The systems andmethods described herein can be used to improve mechanical flexibilityand extend service life of swirlers such as used in fuel injectors forgas turbine engines.

Fuel injector 100 for a gas turbine engine includes an injector bodyhaving a feed arm 104 with a nozzle body 102 connected thereto. A fuelconduit 106 fluidly connects a fuel inlet portion 108 of feed arm 104 toa fuel circuit 110 (not shown in FIG. 1, but see FIG. 2) in nozzle body102 to form a fuel path through the injector body. An outer air swirler112 is operatively connected to nozzle body 102 outboard of fuel circuit110.

With reference to FIG. 2, outer air swirler 112 includes a swirler body,namely barrel 114 with a plurality of axial swirl vanes 116 extendingradially outward from barrel 114. An inner air swirler 118 isoperatively connected to nozzle body 102 inboard of fuel circuit 110.Inner air swirler 118 includes a swirler body, namely inner air swirlerbullet 120, with a plurality of axial swirl vanes 122 extending radiallyoutward from bullet 120.

Referring now to FIG. 3, inner air swirler 118 is shown with theremaining portions of fuel injector 100 removed. Each of the vanes 122includes a spring channel 124 defined therethrough. Each spring channel124 extends from an upstream portion 126 of the respective vane 122 to achannel opening 128 at a trailing edge of the vane 122. Spring channels124 and other embodiments thereof described herein can include a stressreduction feature, e.g., one end of the spring channel can terminate ata stress reducer bore. For example, each of spring channels 124 has aterminus in the respective vane 122 defined by a stress reducer bore 130that has a diameter greater than the width of the channel 124. Bores 130accommodate flexure of vanes 122 without giving rise to undue stressrisers.

With reference now to FIG. 4, it is also contemplated that each of thevanes can include a spring channel defined therethrough, extending froma downstream portion of the vane to a channel opening at a leading edgeof the vane. For example, air swirler 218 includes a bullet 220 withradially extending vanes 222 much as described above with respect to airswirler 118. Like vanes 122 described above, each of vanes 222 includesa sigmoid spring having a first spring channel 224 defined therethrough,extending from an upstream portion 226 of the vane 222 to a channelopening 228 at a trailing edge of the vane 222. In addition, a secondspring channel 232 is defined through each vane 222, radially spacedapart from the respective first spring channel 224 and extending from adownstream portion 234 of the vane 222 to a channel opening 236 at aleading edge of the vane 222. Having two or more spring channels in eachvane provides additional flexibility in applications benefiting frommore mechanical flexibility than is available from a single springchannel. Those skilled in the art will readily appreciate that anysuitable number of spring channels can be included, and that wheremultiple spring channels are used, the spring channels can extend fromthe same edge of the vane, or different edges in any suitablecombination. For example, in embodiments with two spring channels in avane, there are four combinations of spring channel directions that canbe used, depending on what is needed for a given application, includingboth channels extending to the trailing edge of the vane, both channelsextending to the leading edge, the radially outer most channel extendingto the leading edge with the radially inner channel extending to thetrailing edge, and vice versa.

Referring now to FIG. 5, another exemplary inner air swirler 318 isincludes a flexible bullet 320. Bullet 320 has an opening 338 defined ina downstream end thereof. Opening 338 opens into an axial bore 344defined from the downstream end of bullet 320 toward upstream portion340 of bullet 318. Optionally, bore 344 could be defined all of the waythrough bullet 320 axially. A plurality of spring channels 342 aredefined through bullet 318 from the exterior surface thereof, to aninterior surface defined by bore 344. Each channel 342 extends from apoint upstream of opening 338, e.g., in upstream portion 340, andextends downstream to opening 338. Each spring channel 342 extendshelically about bullet 318, spaced circumferentially between the basesof two respective vanes 322. While no spring channels are shown in thevanes 322 of bullet 318, those skilled in the art will readilyappreciate that spring channels such as shown in either of FIGS. 3 and 4can be used in conjunction with spring channels in the bullet of aninner air swirler as shown in FIG. 5, as needed to tailor theflexibility of an inner air swirler for a given application. Springchannels 342 each include a stress reducer bore 331 as described abovewith respect to FIG. 3.

Referring now to FIG. 6, each of the vanes 116 extending radially frombarrel 114 of outer air swirler 112 includes a spring channel 146defined therein, similar to spring channels 124 described above withrespect to FIG. 3, for providing mechanical flexibility in outer airswirler 112. As shown in FIG. 7, in another embodiment of an outer airswirler 212, each vane 216 includes a sigmoid spring with two opposedspring channels 246 and 248, much as described above with respect toFIG. 4. FIG. 8 shows another exemplary embodiment of an outer airswirler 312, wherein spring channels 350 are defined through the barrel314. As shown in FIG. 9, spring channels 350 are similar to springchannels 342 described above with respect to FIG. 5, and wind helicallyaround barrel 314, spaced circumferentially between vanes 316. As withthe inner air swirlers described above, the features of the outer airswirlers in FIGS. 6-8 can be combined in any suitable combination asneeded for a given application. Moreover, although embodiments are shownand described herein with one or two spring channels per vane, thoseskilled in the art will readily appreciate that any suitable number ofspring channels can be used in each vane without departing from thescope of this disclosure. It should be noted that it may be desirable inapplications using swirlers as shown in FIGS. 3 and 6 for the springchannels to extend to alternating edges from vane to vane, e.g., soevery other vane has a spring channel extending from an upstream portionof the vane to the trailing edge of the vane, and the alternating vaneshave their spring channel extending from a downstream portion of thevane to the leading edge of the vane. This can combat torsional loadingfrom the aerodynamic loading of given applications.

With reference to FIG. 10, a portion of another exemplary embodiment ofan inner air swirler 418 with vanes 422 is described. Each vane 422includes a spring channel 424 with a labyrinthine cross-sectionalprofile, which can be seen at openings 428, to inhibit flow leakagethrough the spring channel 424. In other words, the labyrinthinecross-sectional profile of spring channels 424 inhibits leakage of airthrough vanes 422, to promote the intended flow directed by vanes 422.As indicated in FIG. 11, each labyrinthine cross-sectional profileincludes a pair of circumferential segments 452 connected together by aradial segment 454. This labyrinthine cross-sectional profile isexemplary only, and those skilled in the art will readily appreciatethat any other suitable profile can be used without departing from thescope of this disclosure.

Any of the spring channels described herein can incorporate a straightcross-sectional profile, or any suitable labyrinthine cross-sectionalprofile as needed. For example, if a straight cross-sectional profile isused and leakage is unwanted in a particular application, then thechannel width can be tailored so that in most conditions the channel isclosed or nearly closed, e.g., the part surrounding the channel expandsto close the channel width. The swirlers described herein can beproduced using any suitable manufacturing techniques or combination oftechniques including traditional machining and joining techniques aswell as additive manufacturing techniques. Moreover, while inner andouter air swirlers are described herein with flexible components, thoseskilled in the art will readily appreciate that a nozzle or injector canincorporate only a flexible inner air swirler, only a flexible outer airswirler, or both, without departing from the scope of this disclosure.

The mechanical flexibility provided by the spring channels describedherein allows for fuel injectors to operate in more extreme conditionsthan traditional injectors. For example, injectors using the techniquesdescribed herein have flexibility to withstand higher temperaturegradients and more extreme thermal transient events than traditionalinjectors. This can be used to achieve traditional or longer thantraditional injector life in conditions more extreme than appropriatefor traditional injectors. Additionally or alternatively, injectorsusing the techniques described herein can be used in more traditionalconditions with considerably longer life than traditional injectors,e.g., as retrofits. An additional benefit that the techniques describedherein can provide is reduced weight relative to traditional injectors,due to the fact that the flexible structures do not need to be as largein dimension as would rigid components subjected to the same thermalconditions, and to the fact that the spring channels are voids thatlightens parts relative to traditional designs without spring channels.

The methods and systems of the present disclosure, as described aboveand shown in the drawings, provide for swirlers with superior propertiesincluding enhanced mechanical flexibility. While the apparatus andmethods of the subject disclosure have been shown and described withreference to preferred embodiments, those skilled in the art willreadily appreciate that changes and/or modifications may be made theretowithout departing from the spirit and scope of the subject disclosure.

What is claimed is:
 1. A swirler comprising: a swirler body; and aplurality of axial swirl vanes extending radially outward from theswirler body, wherein at least one of the vanes includes a springchannel defined circumferentially through the thickness thereof, whereinthe spring channel is located in the at least one vane extendingradially outward of a base of the vane where the swirl vane connects tothe swirler body, and extending radially inward of a radially outwardtip of the swirl vane, wherein the spring channel is at least one of:the spring channel extending from an upstream portion of the vane to achannel opening at a trailing edge of the vane; and the spring channelextending from a downstream portion of the vane to a channel opening ata leading edge of the vane.
 2. A swirler as recited in claim 1, whereineach of the vanes includes the spring channel defined therethrough,extending from an upstream portion of the vane to a channel opening at atrailing edge of the vane.
 3. A swirler as recited in claim 1, whereineach of the vanes includes the spring channel defined therethrough,extending from a downstream portion of the vane to a channel opening ata leading edge of the vane.
 4. A swirler as recited in claim 1, whereinthe spring channel is a first spring channel, wherein each of the vanesincludes a sigmoid spring including: the first spring channel definedtherethrough, extending from an upstream portion of the vane to achannel opening at a trailing edge of the vane; and a second springchannel defined therethrough radially spaced apart from the first springchannel, extending from a downstream portion of the vane to a channelopening at a leading edge of the vane.
 5. A swirler as recited in claim1, wherein one end of the spring channel terminates at a stress reducerbore.
 6. A swirler as recited in claim 1, wherein the swirler bodyincludes a barrel of an outer air swirler, wherein a plurality of springchannels are defined through the barrel.
 7. A swirler as recited inclaim 6, wherein the spring channels defined through the barrel extendhelically about the barrel.
 8. A fuel injector for a gas turbine enginecomprising: a) an injector body having a feed arm with a nozzle bodyconnected thereto; b) a fuel conduit fluidly connecting a fuel inletportion of the feed arm to a fuel circuit in the nozzle body to form afuel path through the injector body; c) an outer air swirler operativelyconnected to the nozzle body outboard of the fuel circuit, the outer airswirler including a barrel with a plurality of swirl vanes extendingradially outward from the barrel; and d) an inner air swirleroperatively connected to the nozzle body inboard of the fuel circuit,the inner air swirler including an inner aft swirler bullet with aplurality of swirl vanes extending radially outward from the bullet,wherein at least one of the vanes of the outer air swirler, or the swirlvanes of the inner air swirler includes a spring channel definedcircumferentially through the thickness thereof, wherein the springchannel is located in the at least one vane extending radially outwardof a base of the vane, and extending radially inward of a radiallyoutward tip of the swirl vane, wherein the spring channel is at leastone of: the spring channel extending from an upstream portion of thevane to a channel opening at a trailing edge of the vane; or the springchannel extending from a downstream portion of the vane to a channelopening at a leading edge of the vane.
 9. A fuel injector as recited inclaim 8, wherein one end of the spring channel terminates at a stressreducer bore.
 10. A fuel injector as recited in claim 8, wherein thespring channel is a first spring channel, wherein each of the vanes ofat least one of the inner air swirler or outer air swirler includes asigmoid spring including: the first spring channel defined therethrough,extending from an upstream portion of the vane to a channel opening at atrailing edge of the vane; and a second spring channel definedtherethrough radially spaced apart from the first spring channel,extending from a downstream portion of the vane to a channel opening ata leading edge of the vane.